Alternative Models for Correlating Toxic Effects

Two very different types of correlation are examined. First, the problem of correlating two different toxic potentials, such as mutagenesis and carcinogenesis, over a class of chemicals is discussed and shown to be quite difficult unless strong assumptions are made about the dose-response curves for each effect. The second type of correlation is that of joint occurrences of symptoms over a population of subjects. A latent class model whose parameters are linear functions of dosage is proposed based on a two-stage theory of carcinogenesis. This model surpasses various alternative models in predicting multiple site tumors resulting from exposure to the solvent 1,3-butadiene.